Alright I use insight and tried to follow what others were talking about with using the proxys. They Were all confusing so I'll give a few steps to help.

1) Make sure all firewalls are configured to work with limewire. (port 6346)
2) Next if you cant connect or cant search then you'll need a proxy.
3) I used the site http://www.publicproxyservers.com/page1.html
4) I found the US proxys to work best. Pick a random one and try it. To use it go to TOOLS>OPTIONS>ADVANCED>PROXY
5) Then enter the proxy of your choice. Make sure you select that its a HTTP proxy.
6) If you still cannot connect in about 5mins then try out another proxy.
7) Also make sure every time you enter a new proxy or change your settings to dissconnect and connect from the network. This will renew all settings.

I hope this helps a little better than those other explainations. Good Luck